Applications for radio frequency identification systems

ABSTRACT

The present invention relates to RFID devices, including handheld RFID devices, and applications for such devices. The devices and applications may be used in connection with items that are associated with an RFID tag, and optionally a magnetic security element. The devices and applications are described with particular reference to library materials such as books, periodicals, and magnetic and optical media.

RELATED APPLICATIONS

[0001] This patent application is a division of application Ser. No.09/619,220, filed Jul. 19, 2000, which is a division of application Ser.No. 09/368,826, filed Aug. 5, 1999 (now U.S. Pat. No. 6,232,870), whichis a continuation-in-part of U.S. application Ser. No. 09/344,758, filedJun. 25, 1999 (now abandoned), which is a continuation-in-part of U.S.application Ser. No. 09/134,686, filed Aug. 14, 1998 (now abandoned).

INCORPORATION BY REFERENCE

[0002] This patent application claims priority from U.S. applicationSer. No. 09/134,686, filed Aug. 14, 1998 with the same title, and U.S.application Ser. No. 09/344,758, filed Jun. 25, 1999 with the sametitle, both of which were assigned to the assignee of the presentinvention, and the contents of both of which are incorporated byreference herein.

TECHNICAL FIELD

[0003] The invention relates to applications for radio frequencyidentification (RFID) systems, and particularly to the use of suchsystems in libraries.

BACKGROUND OF THE INVENTION

[0004] Electronic article surveillance (“EAS”) systems detect thepresence of small electronic devices placed on or in an article orcarried by a person of interest, and are often used in retail or libraryenvironments to deter theft or other unauthorized removal of articles.These devices, which are commonly known as tags or markers, have in thepast contained only information regarding the presence of an item. Thisinformation could be obtained by electronically interrogating the tag,either intermittently or continuously. At least four distinct types ofEAS systems have evolved over the years, based on how this interrogationwas carried out: magnetic, magnetomechanical, radio frequency (RF), andmicrowave. Of these four, magnetic systems have provided the highestlevel of security in most applications. Magnetic tags are easily hiddenin or on an object, difficult to detect (because they are lesssusceptible to shielding, bending, and pressure), and easy to deactivateand reactivate, thereby providing a high degree of security and someinformation regarding the status of the tagged article.

[0005] Many users of EAS systems desire to know more than just whether atagged object is present. They also want to know which tagged object ispresent, for example. Detailed information regarding the characteristicsof objects, such as their date of manufacture, inventory status, andowner have generally been communicated to automated handling and controlsystems through an optical bar code. While inexpensive and effective,the optical bar code system has certain limitations. Bar codes must bevisible, which limits the locations in which they may be placed, and barcodes can easily be obscured, either accidentally or intentionally. Therange at which a detector can sense the bar code is also comparativelysmall. The bar code may also have to be appropriately positioned fordetection. Also, because bar codes are often exposed to permitdetection, the barcode is susceptible to damage that can result indetection failures. Lastly, multiple items must be processed one at atime. These constraints of bar code systems make them undesirable orinefficient for some applications, such as marking library media.

[0006] More recently, electronic identification (also known as radiofrequency identification or RFID) techniques have been developed toaddress the limitations of optical barcodes. RFID systems have succeededin providing object identification and tracking, but are deficient inproviding object security because most RFID systems operate in frequencyranges (˜1 MHz and above) in which the tag is easily defeated. Thesecurity deficiency associated with radio frequency tags arises becausethey can be “shielded” by, for example, covering the tag with a hand oraluminum foil, or even placing the tag in a book. Even battery-poweredradio frequency tags may be blocked, although their range is superiorand blocking would be more difficult. Thus, objects tagged with an RFIDtag may escape detection, either inadvertently or intentionally. Thisgreatly reduces their effectiveness as security devices. RFID markersare also related to “smart cards.” Both contact and contactless smartcards have appeared in commercial applications. Smart cards tend to beassociated with a specific person rather than with a tagged object.Issues related to the security and tracking of the smart card (or of theperson carrying it) are similar to those discussed above for RFIDmarkers.

[0007] The security issues associated with RFID markers are similar tothose familiar to anyone skilled in the art of radio frequency- andmicrowave-based EAS tags. Substantial effort has been expended inattempts to remedy the deficiencies of radio frequency- andmicrowave-based EAS tags. However, none has substantially improved theirperformance as security tags. U.S. Pat. No. 5,517,195 (Narlow et al.),entitled “Dual Frequency EAS Tag with Deactivation Coil,” describes adual frequency microwave EAS tag that includes an antenna circuit havinga diode, and a deactivation circuit. The deactivation circuit respondsto a low energy alternating magnetic field by inducing a voltage in thediode of the antenna circuit so as to disable the diode and the antenna,thereby deactivating the tag. Although useful for some applications, thecapacitor-based tag disclosed in Narlow et al. may leak electricalcharge over time, which could cause the tag to become activatedunintentionally.

[0008] Radio frequency EAS tags of the type disclosed in U.S. Pat. No.4,745,401 (Montean et al.) include a magnetic element. The magneticelement alters the tuning of the tag when it has been suitablymagnetized by an accessory device, and thereby blocks the radiofrequency response of the tag. Although these tags have a certainutility, they still do not address the issues of enhanced security andidentification.

[0009] Radio frequency identification technology has been developed by anumber of companies, including Motorola/Indala (see U.S. Pat. Nos.5,378,880 and 5,565,846), Texas Instruments (see U.S. Pat. Nos.5,347,280 and 5,541,604), Mikron/Philips Semiconductors, Single ChipSystems (see U.S. Pat. Nos. 4,442,507; 4,796,074; 5,095,362; 5,296,722;and 5,407,851), CSIR (see European document numbers 0 494 114 A2; 0 585132 A1; 0 598 624 A1; and 0 615 285 A2), IBM (see U.S. Pat. Nos.5,528,222; 5,550,547; 5,521,601; and 5,682,143), and SensormaticElectronics (see U.S. Pat. No. 5,625,341). These tags all attempt toprovide remote identification without the need for a battery. Theyoperate at frequencies ranging from 125 KHz to 2.45 GHz. The lowerfrequency tags (˜125 KHz) are moderately resistant to shielding, buthave only limited radio frequency functionality due to bandwidthconstraints. In particular, systems based on these markers generallyoperate reliably only when a single tag is in the interrogation zone ata time. They also tend to be relatively bulky and expensive tomanufacture. At higher frequencies, (typically 13.56 MHz, 915 MHz, and2.45 GHz), the added bandwidth available has permitted the developmentof systems which can reliably process multiple tags in the interrogationzone in a short period of time. This is highly desirable for manyproduct applications. In addition, some of the tag designs hold thepromise of being relatively inexpensive to manufacture and thereforemore attractive to a customer. However, these higher frequency devicesshare to varying degrees the susceptibility to shielding discussedearlier. Thus, they cannot provide the high level of security demandedin certain applications, such as a library.

[0010] From the foregoing discussion, it should be clear that there area number of applications for RFID tags in various environments in whichthe identity of the tagged item is important. For example, PCTPublication WO 99/05660, published Feb. 4, 1999 and assigned toCheckpoint Systems, Inc., describes an inventory system using articleswith RFID tags. The preferred embodiment described therein contemplatesthe use of RFID tags in library materials, which may then be checked outautomatically by interrogating the RFID tag to determine the identity ofthe material. However, a number of important or desirable library orother inventory functions remain that are not described or suggested inthe '660 publication.

SUMMARY OF THE INVENTION

[0011] The present invention relates to RFID devices, including handheldRFID devices, and applications for such devices. The devices andapplications may be used in connection with items that are associatedwith an RFID tag, and optionally a magnetic security element. Thedevices and applications are described with particular reference tolibrary materials such as books, periodicals, and magnetic and opticalmedia. Other applications for the present invention are also envisioned.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is described in greater detail withreference to the attached Figures, in which like numbers represent likestructure throughout the several views, and in which

[0013]FIGS. 1A and 1B are schematic illustrations of radio frequencyidentification tags;

[0014]FIG. 2 is a schematic of a second embodiment of a radio frequencyidentification tag;

[0015]FIG. 3 is a schematic top view of a combination tag;

[0016]FIG. 4 is a block diagram of an RFID interrogation systeminteracting with an RFID tag;

[0017]FIGS. 5, 6, 7, and 8 are illustrations of combination tagsaccording to the present invention; and

[0018]FIGS. 9, 10, 11, 12, 13, and 14 are illustrations of variousembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The embodiments of the present invention described herein makeuse of RFID tags, and preferably of combination RFID/magnetic securitytags. Tags of this type were disclosed in U.S. application Ser. No.09/093,120, filed Jun. 8, 1998 and entitled “Identification Tag WithEnhanced Security,” which was assigned to the assignee of the presentinvention and was incorporated by reference into the U.S. applicationfrom which the present application claims priority. A detaileddescription of the magnetic, RFID, and combination tags used inconjunction with the embodiments of the present invention is describedin Section I, below, and the embodiments of the present invention arethen set forth in detail in Section II, below.

I. Tags and Elements For Use With Embodiments of the Present Invention

[0020] A tag used with the embodiments of the invention described inSection II, below, may incorporate both object identification andeffective security in a single device. They preferably include anelement that is responsive to a magnetic interrogation signal, and anelement that is responsive to a radio frequency interrogation signal. Inone embodiment, the magnetically-responsive element also provides theantenna for the radio frequency-responsive element. The term“responsive” means, in the context of the present invention, that theelement provides intelligible information when subjected to anappropriate interrogation field. The individual elements are describedfirst below, followed by a description of a combination tag. As willbecome apparent, the embodiments of the present invention described inSection II, below, may include either an RFID element alone, or acombination of an RFID element and a magnetic security element.

[0021] A. The Magnetically-Responsive Element

[0022] The magnetically-responsive element is preferably made of a lowcoercive force, high permeability ferromagnetic material, such as thematerial used in the strips sold by the Minnesota Mining andManufacturing Company of St. Paul, Minn. (3M) under the designation“TATTLE-TAPE™” brand strips. These strips, or marker assemblies, aredescribed in several patents assigned to 3M, including U.S. Pat. Nos.5,331,313 (Koning) and 3,747,086 (Peterson), the contents of which areincorporated by reference herein. Exemplary low coercive force, highpermeability ferromagnetic materials include permalloy (a nickel/ironalloy), and high performance amorphous metals such as those availablefrom the AlliedSignal Company of Morristown, N.J. under the designationsMetglas 2705M and Metglas 2714A.

[0023] The magnetically-responsive element may be either single statusor dual status, depending on the nature of the article with which theelement is associated. For example, certain reference books in librariesare not to be removed from the library, and thus a single-status(non-deactivatable) marker would always indicate whether such a bookpassed within an interrogation zone. Other articles, such as commonlibrary materials or commercial goods, may require a dual-status markerassembly, so that when the article has been properly processed themarker may be appropriately deactivated to prevent detection by theinterrogation source. Dual status functionality is generally providedthrough the addition of sections of higher coercivity magnetic materialin proximity to the low coercivity magnetic material, as described belowand in the Peterson patent incorporated by reference above.

[0024] Certain magnetically-responsive elements have the ability toswitch magnetic orientation rapidly when passed through a low frequencyalternating magnetic field (50 Hz to 100 KHz, for example), and toproduce a predetermined characteristic response that may be detected bythe receiving coils of a detector. The switching function of the markerassembly is controlled by the magnetization state of the high coerciveforce elements, or “keeper elements.” When these keeper elements aremagnetized, the ability of the marker to magnetically switch back andforth within the alternating magnetic field of the interrogation zone isaltered, and the marker typically is not detected. When the keeperelements are demagnetized, the marker can again perform the switchingfunction, enabling the interrogation source to detect the presence ofthe marker. The keeper elements may be provided in different ways, as isknown in the art.

[0025] The marker assembly may also include adhesive on one or bothsides thereof, to enable the marker to be bonded to a book or otherarticle. The adhesive layer(s) may be covered by a removable liner, toprevent adhesion of the marker to an unintended surface prior toapplication to the intended surface. These and other features of themarker assembly are described in the U.S. Pat. Nos. 3,790,945 (Fearon),5,083,112 (Piotrowski), and 5,331,313 (Koning), all incorporated byreference above.

[0026] Because low frequency magnetic elements of this type aredifficult to shield from detection, they may be effectively used on awide variety of items when security is important. In addition, they maybe deactivated and reactivated more conveniently, completely, andrepeatedly than markers employing other EAS technologies, making themmore suitable for use in certain applications (such as libraries) wherethis characteristic is highly desirable.

[0027] B. The Radio Frequency-Responsive Element

[0028] RFID tags can be either active or passive. An active tagincorporates an additional energy source, such as a battery, into thetag construction. This energy source permits active RFID tags to createand transmit strong response signals even in regions where theinterrogating radio frequency field is weak, and thus an active RFID tagcan be detected at greater range. However, the relatively short lifetimeof the battery limits the useful life of the tag. In addition, thebattery adds to the size and cost of the tag. A passive tag derives theenergy needed to power the tag from the interrogating radio frequencyfield, and uses that energy to transmit response codes by modulating theimpedance the antenna presents to the interrogating field, therebymodulating the signal reflected back to the reader antenna. Thus, theirrange is more limited. Because passive tags are preferred for manyapplications, the remainder of the discussion will be confined to thisclass of tag. Those skilled in the art, however, will recognize thatthese two types of tags share many features and that both can be usedwith this invention.

[0029] As shown in FIG. 1, a passive radio frequency-responsive element10 typically includes two components: an integrated circuit 12 and anantenna 14. The integrated circuit provides the primary identificationfunction. It includes software and circuitry to permanently store thetag identification and other desirable information, interpret andprocess commands received from the interrogation hardware, respond torequests for information by the interrogator, and assist the hardware inresolving conflicts resulting from multiple tags responding tointerrogation simultaneously. Optionally, the integrated circuit mayprovide for updating the information stored in its memory (read/write)as opposed to just reading the information out (read only). Integratedcircuits suitable for use in RFID markers include those available fromTexas Instruments (in their TIRIS or TAG-IT line of products), Philips(in their I-CODE, MIFARE and HITAG line of products), Motorola/Indala,and Single Chip Systems, among others.

[0030] The antenna geometry and properties depend on the desiredoperating frequency of the RFID portion of the tag. For example, 2.45GHz (or similar) RFID tags would typically include a dipole antenna,such as the linear dipole antennas 14 shown in FIG. 1A, or the foldeddipole antennas 14 a shown attached to the radio frequency responsiveelement 10 a in FIG. 1B. A 13.56 MHz (or similar) RFID tag would use aspiral or coil antenna 14 b, as shown attached to the radio frequencyresponsive element 10 b in FIG. 2. In either ease, the antenna 14intercepts the radio frequency energy radiated by an interrogationsource. This signal energy carries both power and commands to the tag.The antenna enables the RF-responsive element to absorb energysufficient to power the IC chip and thereby provide the response to bedetected. Thus, the characteristics of the antenna must be matched tothe system in which it is incorporated. In the case of tags operating inthe high MHz to GHz range, the most important characteristic is theantenna length. Typically, the effective length of a dipole antenna isselected so that it is close to a half wavelength or multiple halfwavelength of the interrogation signal. In the case of tags operating inthe low to mid MHz region (13.56 MHz, for example) where a halfwavelength antenna is impractical due to size limitations, the importantcharacteristics are antenna inductance and the number of turns on theantenna coil. For both antenna types, good electrical conductivity isrequired. Typically, metals such as copper or aluminum would be used,but other conductors, including magnetic metals such as permalloy, arealso acceptable and are, in fact, preferred for purposes of thisinvention. It is also important that the input impedance of the selectedIC chip match the impedance of the antenna for maximum energy transfer.Additional information about antennas is known to those of ordinaryskill in the art from, for example, reference texts such as J. D. Kraus,Antennas (2d ed. 1988, McGraw-Hill, Inc., New York).

[0031] A capacitor 16 is often included to increase the performance ofthe marker, as shown in FIG. 2. The capacitor 16, when present, tunesthe operating frequency of the tag to a particular value. This isdesirable for obtaining maximum operating range and insuring compliancewith regulatory requirements. The capacitor may either be a discretecomponent, or integrated into the antenna as described below. In sometag designs, particularly tags designed to operate at very highfrequencies, such as 2.45 GHz, a tuning capacitor is not required. Thecapacitor is selected so that, when coupled to the inductance providedby the antenna, the resonant frequency of the composite structure, givenby: $f_{r} = {( \frac{1}{2\pi} )\sqrt{\frac{1}{LC}}}$

[0032] where

[0033] C=capacitance (in Farads)

[0034] L=inductance (in Henries)

[0035] closely matches the desired operating frequency of the RFIDsystem. The capacitor may also be a distributed capacitor as describedin U.S. Pat. Nos. 4,598,276 (Tait et al.) and 4,578,654 (Tait et al.),which are assigned to 3M. Distributed capacitance is desirable to reducetag size, particularly thickness, and to minimize manual assembly.

[0036] In operation, as shown in FIG. 4, the radio frequency-responsivetag 110 is interrogated by an EAS security system 100, which istypically located near the point at which the tags are to be monitored.An interrogation zone may be established by placing spaced detectionpanels across the exits from the room in which the tagged articles arelocated, near a conveyor carrying items to be monitored, or the like.Hand held detection devices may also be used. An interrogation source102 (typically including a drive oscillator and an amplifier) is coupledto an antenna 104 (sometimes described as a field coil) for transmittingan alternating radio frequency field, or interrogation signal, in theinterrogation zone. The system 100 also includes an antenna forreceiving a signal (shown as antenna 104, and sometimes described as areceiving coil) and detector 106 for processing signals produced by tagsin the interrogation zone.

[0037] The interrogation source 102 transmits an interrogation signal200, which may be selected within certain known frequency bands that arepreferred because they do not interfere with other applications, andbecause they comply with applicable government regulations. When theradio frequency-responsive element receives an interrogation signal ittransmits its own response code signal 202 that is received by theantenna 104 and transmitted to detector 106. The detector decodes theresponse, identifies the tag (typically based on information stored in acomputer or other memory device 108), and takes action based on the codesignal detected. Various modifications of the illustrated system areknown to those of skill in the art including, for example, usingseparate antennas for the interrogation source 102 and the detector 106in place of the single antenna 104 that is illustrated.

[0038] Modern RFID tags also provide significant amounts of useraccessible memory, sometimes in the form of read-only memory orwrite-once memory, but more preferably offering the user the ability torepeatedly update the memory by rewriting its contents from a distance.The amount of memory provided can vary, and influences the size and costof the integrated circuit portion of an RFID tag. Typically, between 128bits and 512 bits of total memory can be provided economically. Forexample an RFID tag available from Texas Instruments of Dallas, Texas,under the designation “Tag-it” provides 256 bits of user programmablememory in addition to 128 bits of memory reserved for items such as theunique tag serial number, version and manufacturing information, and thelike. Similarly, an RFID tag available from Philips Semiconductors ofEindhoven, Netherlands, under the designation “I-Code” provides 384 bitsof user memory along with an additional 128 bits reserved for theaforementioned types of information.

[0039] This user accessible memory may be exploited to enhance theperformance of an item identification system deployed, for example, in alibrary environment. Presently, libraries identify items by scanning anoptical barcode. The unique identifier contained in this barcode is usedto access a circulation database including software provided by libraryautomation vendors (LAV software), where more extensive informationabout the item is permanently maintained. While this system has beenhighly developed and works very well in many applications, it may havetwo disadvantages. First, a connection to the circulation database mustbe established to access the information. This limits the availabilityof the information when an item is at a location remote from aconnection to this database. Second, the retrieval of information fromthe circulation database can sometimes require an unacceptably longtime, particularly during periods of heavy use. By storing certaincritical items of information on the RFID tag, both of these limitationscan be overcome.

[0040] One example of information which could improve the performance ofa library identification system if present on the RFID tag itself wouldbe a library identification number. Then, without accessing a database,an item's “home” library could be quickly and conveniently determined bysimply scanning the RFID label. Another example of informationpreferably present on an RFID tag itself would be a code designatingwhether the item was a book, a video tape, an audio tape, a CD, or someother item. This code could, for example, comprise the media type codespecified in the 3M Standard Interchange Protocol, which is availablefrom the assignee of the present invention. By immediately knowing themedia type, a library's material management systems could insure that anitem was being appropriately processed without incurring the delay andinconvenience of consulting a remote circulation database. Otherexamples of information suitable for incorporation into the RFID labelwill be apparent to those skilled in the art.

[0041] Another area in which RFID systems offer an advantage overbarcode-based systems is in the identification of multiple items. Byusing sophisticated software algorithms, RFID readers and markerscooperate to insure that all items in the reader's interrogation zoneare successfully identified without intervention by the operator. Thiscapability enables the development of numerous useful applications inthe areas of inventory control, item tracking, and sorting that would bedifficult or impossible to implement with barcode-based identificationsystems.

[0042] C. The Combination Tag

[0043] As shown in FIGS. 3 and 5 through 8, the combination tag 20combines a magnetically-responsive element with an RF-responsive elementto provide the advantages of both. Thus, the two elements can be appliedto an item of interest at the same time, thereby reducing cost. Thecombination tag may be provided with a pressure sensitive adhesivecovered by a removable liner, which enables the combination tag to beadhered to a surface of the article when the liner has been removed. Inanother embodiment, the tag uses the magnetically-responsive element asan antenna for the radio frequency-responsive element. Themagnetically-responsive element, when used as an antenna, iselectrically coupled to the radio frequency-responsive element, and mayor may not also be physically coupled to the radio frequency-responsiveelement.

[0044] The combination tag made according to the present invention maybe interrogated two ways. First, the RFID interrogation source would useradio frequency signals to request and receive codes from the integratedcircuit. This information would indicate, for example, theidentification of the article with which the tag is associated, andwhether the article had been properly processed. Second, a magneticinterrogation field would interrogate the tag to determine whether themagnetic portion of the marker assembly was active. If the markerassembly was active, the interrogation source would produce a response,such as a notification that the marked article had not been properlyprocessed. Because the magnetic interrogation is more resistant toshielding than the radio frequency interrogation, the magnetic portionof the combination tag would provide enhanced security. Thus, thefeatures of both magnetic and RFID tags are combined into a singlecombination tag.

[0045] In a preferred embodiment, the combination tag includes amagnetically-responsive element that also functions as the antenna inthe circuitry of the radio frequency-responsive element. To serve bothfunctions, the antenna material must exhibit low magnetic coercivity andvery high magnetic permeability (to serve as an efficient securityelement), and moderate to high electrical conductivity (to function asan efficient antenna). In addition, the geometry of the antenna must becompatible with both functions. In this embodiment, the antenna could,for example, be fabricated from permalloy, an alloy of nickel and iron.

[0046] In one embodiment, a 3M “Tattle-Tape™” brand security strip, orother equivalent magnetic element, may be used as a linear dipoleantenna to operate at 2.45 GHz or a similar high frequency. The length,width and thickness of this strip are selected to match the particularoperating frequency and other characteristics of the RFID chip used.Typically, the strip would be made from permalloy (available from anumber of sources including Carpenter Specialty Alloys, Reading, Pa.,under the trade name “HyMu80”) or an amorphous alloy such as thatavailable from the AlliedSignal Company of Morristown, N.J., under thedesignation 2705M, and its length would be between 6.35 and 16.5 cm (2.5and 6.5 inches). The terminals of the integrated circuit would bephysically connected to the ends of the security strip. Electricalmeasurements of impedance and power gain have established that such amagnetic strip provides the same fundamental electrical characteristicsas the copper or aluminum dipole antennas normally used with such achip, and thus it would be expected to perform both functionssatisfactorily.

[0047] When the magnetically-responsive element is used as at least partof the antenna for the radio frequency-responsive element, the two areelectrically coupled to each other. Electrical coupling may occurbecause of a physical connection between multiple elements (as shown inFIG. 5), or, in the absence of a physical connection, by non-contactelectromagnetic coupling (as shown in FIGS. 6, 7, and 8). Non-contactcoupling can include parasitic coupling, capacitive coupling, orinductive coupling, and use such antenna components as parasitic antennaelements, reflector and director antennas, Yagi-Uda antennas, or othersuitable antenna configurations.

[0048] The combination tag shown in FIG. 3 includes coil turns made frommagnetic material. The tag could be, for example, a 13.56 MHz tag havingan antenna structure such as 14 c in which flux collectors are providedat the comers to improve the magnetic function of the tag. Other typesof flux collectors may be provided.

[0049] The combination tag 20 shown in FIG. 5 includes a physicalconnection between the antenna 22, which is made ofmagnetically-responsive material, and the integrated circuit 12. One ormore keeper elements or the type described above also may be applied tothe magnetically-responsive material, so that it may be selectivelyactivated and deactivated to provide a dual status tag. The antenna 22 ashown in FIG. 6, however, is not physically connected to the integratedcircuit 12 or the dipole antenna 23, but is nonetheless electricallycoupled to the dipole antenna by parasitic dipole coupling to provide acombination tag 20 a. The dipole antenna 23 may comprise eithermagnetically-responsive material or non-magnetically-responsivematerial.

[0050]FIGS. 7 and 8 illustrate embodiments in which more than oneantenna 22 is provided to electrically couple with antennas 23 b and 23c, respectively. In the combination tag 20 b shown in FIG. 7, integratedcircuit 12 includes dipole antenna 23 b, which is parasitically coupledto antennas 22 b. Antennas 22 b are made of magnetically-responsivematerial, and antenna(s) 23 b may be made of magnetically-responsivematerial. In the combination tag 20 c shown in FIG. 8, a radiofrequency-responsive element of the type shown in FIG. 2 isparasitically electrically coupled to antennas 22 c. Antennas 22 c aremade of magnetically-responsive material, and antenna(s) 23 c may bemade of magnetically-responsive material. Other variations of theseembodiments are easily designed.

[0051] The overall thickness of the combination tag should be as smallas possible, to enable the tag to be inconspicuously placed on or in anarticle. For example, the tag may be applied with adhesive between thepages of a book, and it is desirable to make the tag thin enough toprevent easy detection by observing the end of the book. ConventionalICs may be approximately 0.5 mm (0.02 in) thick, and the overallthickness of the tag is preferably less than 0.635 mm (0.025 in).

[0052] The combination tags of this invention may be provided in rollform, to enable the automated sequential application of individual tagsto articles. This general system is described in, for example, PCTPublication No. WO 97/36270 (DeVale et al.). Individual combinationtags, one or more surfaces of which may be covered by an adhesive (suchas a pressure sensitive adhesive), may be removed from the roll andapplied between two pages of a book, near its binding. A page spreadermay be provided to facilitate insertion of the combination tag, andother options such as sensors to detect the position of variouscomponents in the system may also be provided.

[0053] The combination tag is believed to have particular, although notexclusive, use in the processing of library materials. Library materialshaving an RFID tag of this type could be checked in and out more easily,perhaps without human assistance. That is, the materials wouldautomatically be checked out to a particular patron (who may herselfhave an RFID tag associated with her library card) when the patronpasses through a suitable detection zone, and checked back in when thepatron re-enters the library with the materials. The tag of theinvention may also assist in inventory management and analysis, byenabling library administrators to keep track of materialsinstantaneously and continuously. These and other features of theinvention can, of course, be brought to bear on other applications, suchas materials handling in stores, warehouses, and the like.

[0054] In another embodiment, the combination tag could providedual-status marker information both through a magnetic response(indicating whether the magnetic features of the tag had been activatedor deactivated) and through a radio frequency response (indicating,through the use of appropriate software, whether the database or thememory on the RFID chip itself showed that the item had beenappropriately processed).

[0055] The following Examples provide still further information as tothe tags used in the embodiments of the invention described in SectionII, below.

EXAMPLE ONE

[0056] A combination tag was made in accordance with the presentinvention. A permalloy strip produced from an alloy available from theCarpenter Technology Corporation of Reading, Pa. under the designation“HyMu80” was attached to a test fixture manufactured by Single ChipSystems (SCS) of San Diego, Calif. The strip measured approximately 1.6mm (0.625 in) wide by 0.0254 mm (0.001 in) thick by 10.16 cm (4 in)long. The test fixture consisted of a standard SCS 2.45 GHz antennaconnected to an LED diode. The device was designed so that upon exposureto a 2.45 GHz field strong enough to power a typical SCS RFID tag theLED would glow, providing an immediate visible confirmation of theproper operation of the power-receiving portion of the device. Uponreplacing the standard SCS antenna with the prototype permalloy antenna,the LED illuminated at approximately the same field strength, confirmingthe successful operation of the prototype.

EXAMPLE TWO

[0057]FIG. 3 illustrates another embodiment of an antenna that isbelieved useful with a 13.56 MHz RFID design. At this frequency, acoil-type antenna geometry is preferred. The spiral turns comprising thecoil are formed from a magnetic alloy such as permalloy, either byetching (physical or chemical), die cutting, or deposition through amask. The straight “arm” portions of the coil serve also as themagnetically responsive elements in this design. However, the reducedlength of these metallic elements in this geometry limits theeffectiveness of the magnetic security portion of the device. In theembodiment shown in FIG. 3, flux collection elements provided at thecorners have been added to the antenna coil to overcome this limitation.The construction shown in FIG. 3 would, preferably, include a capacitoras previously described to tune the operating frequency of the antennato the prescribed interrogation frequency.

[0058] The characteristics of the antenna described in this example werecompared with the characteristics of known antennas for radio frequencyintegrated circuits, and because those characteristics were similar, itis believed that the antenna of this example would function adequatelyin such an application.

[0059] The embodiments of the present invention described below may useeither a tag having only an RFID element, or a combination tag, both ofwhich are described above.

II. Embodiments of the Present Invention

[0060] A. RFID Device with Magnetic Capabilities.

[0061] Because RFID tags may be shielded either intentionally orunintentionally by a library patron, it is often important to provideboth RFID and magnetic security elements in the tagged library material,preferably on the same tag. When the magnetic security element is dualstatus, meaning that it may be selectively activated and deactivated,its status is typically changed by the application of a magnetic fieldto that element. Magnetization operations such as this have no effect onlibrary materials such as books and magazines, but can have harmfuleffects on magnetically-recorded media. The inventive RFID device withmagnetic capabilities solves such problems, preferably without anyinvolvement by library staff members.

[0062] As shown in FIG. 9, an RFID device is equipped to readinformation from an RFID tag on an item, such as a patron card, book, orother material. Preferably, the information read from the RFID tagincludes a designation of media type (magnetic, print, or optical, forexample), which can be used to insure the proper subsequent processingof the item. The RFID device is also equipped with a device, such as thecoil, designed to enable the activation and deactivation of the securityelement portion of the item tag. After the RFID device reads the RFIDtag, the device transmits the item identification information to acomputer having software provided by a library automation vendor, orLAV. Among approximately 50 current LAV software systems are “Dynix,”which is available from Ameritech Library Services of Provo, Utah, “CarlILS” which is available from CARL Corporation of Denver, Colo., and“DRA,” which is available from DRA, of St. Louis, Mo.

[0063] There are a number of ways to transmit the information obtainedfrom an RFID tag to the LAV system. One would involve using the commandsimplemented in the 3M Standard Interchange Protocol (SIP). Another wouldinvolve using an electronic device known as a “wedge” to transmit theinformation as if it originated from a conventional barcode scanner.These and other techniques are well-known to those skilled in the art.In this manner, the RFID component of the RFID device performs thefunctions formerly performed by an optical bar-code scanner, which mayor may not continue to be used with the device. Thus, libraries maycontinue to use their existing LAV software system interfaces andterminals while enjoying the added functionality and features providedby RFID technology. The RFID device need not include a display if itwould cooperate with an existing LAV software system display to providefeedback to the operator. Optionally, a display and other feedbackmechanisms may be included in the RFID device as an integrated package.

[0064] In devices having both RF and optical bar code readingcapabilities, the device should be able to handle library materialstagged with RF tags, bar code labels, or both. In operation, the devicewould process an item for check-in by scanning for an RFID tag, abarcode, or both, retrieving the item identification code and,preferably, the media type from one or both of these tags, and passingthis information on to the LAV software system. When the device includesboth an RFID system and an optical bar code scanning system, the devicemay also be used to create RFID tags for media that is, only bar-coded.First, the bar code would be scanned, and then the identifier (or an IDcode associated with that identifier, depending on system design) wouldbe written to (recorded onto) the RFID tag along with other data, suchas media type and other selected information returned from the LAVsoftware system relative to that media. The RFID tag could then beapplied to the item.

[0065] The RFID device of the present invention preferably also performs“smart” resensitizing and desensitizing of the magnetic securityelements attached to library materials. When the device reads the RFIDtag and transmits the identification information to the LAV software,the LAV software can be programmed to respond with an indication of thetype of library material with which the RFID tag is associated. If theLAV software responds with an indication that the tagged material issomething for which a specialized magnetization operation is required(magnetically-recorded media, typically), then the device can activateonly the system that performs that operation. For example, if the LAVsoftware indicates that the RFID tag is associated with an ordinarybook, and that the book may be checked out by the requesting patron,then one magnetization system may be activated to deactivate themagnetic element associated with that book. However, if the LAV softwareindicates that an RFID tag is associated with a video tape, for example,then a different magnetization system may be activated to deactivate themagnetic security element associated with that video tape. Thisdifferent magnetization system might involve, for example, a weakermagnetic field or a field confined to the region in the immediatevicinity of the security element, so as to prevent damage to themagnetic media itself, depending on the detailed characteristics of thesecurity tags in use. Depending on the detailed design of the device,the procedure might include inhibiting automatic activation so as not todamage magnetic media.

[0066] Preferably, sufficient information may be stored in the memory ofthe RFID tag itself that the interrogation source need not transmit thatinformation to the LAV software, and can instead invoke the appropriatemagnetization system directly. This embodiment would likely improvesystem performance, because fewer steps are required to reach the sameresult. As a minimum, the RFID tag should store a media type in thememory of the RFID element, but could as noted above include additionalinformation. This type of processing, without transmission back to adatabase separate from the RFID device, is referred to herein ashappening in “real time.”

[0067] An advantage of an RFID device such as that described is that itmay accept and process items with less dependence on their orientationrelative to the device. Thus, although a library material may beprocessed by an optical bar code scanner only when the bar code label isproperly positioned and readable by the scanner, a book having an RFIDtag or combination tag may be positioned with front cover either up ordown, and without the need to carefully align a label with a scanner.This advantage of RFID systems over conventional optical and bar codesystems results in considerable time savings for patrons and librarystaff. The “read range” may be different with different scanners, tags,and other components, but it is believed that a read range ofapproximately 15 centimeters (6 inches) would be satisfactory. Tofacilitate reliable RFID scanning, however, it may be desirable toposition the RFID tags for various items at the same fixed positionrelative to an edge of the item. For example, RFID tags provided onlibrary books might all be positioned 2 inches above the bottom of thebook.

[0068] The benefits of the inventive RFID device are numerous andsignificant, and include having only a single station at which toidentify, resensitize, and desensitize library materials, theelimination of operator training on and performance of differentmagnetization operations, increased processing speed due to thereduction of orientation constraints present in bar-code only systems,and decreased likelihood of repetitive stress injury to operators.Another benefit is that it is faster to scan RFID tags than to read abar code, especially for codes that are inside the cover or case of theitem, in large part because the user need not locate and align a barcode. Lastly, the system also is a low cost one because RFID readers areexpected to cost less than high-performance bar-code scanners. These andother benefits and advantages will be apparent to one of skill in theart.

[0069] B. Use of RFID Device with Multiple Items.

[0070] Another benefit of an RFID device is the ability to processmultiple items at one time, as shown in FIG. 10. Whereas conventionaldevices having only optical bar code scanners can process only a singleitem presented to the bar code scanner at one time, a group of itemshaving RFID elements may be processed essentially simultaneously. Thismay be achieved by having multiple RFID interrogation sources (readers)mounted in or on the device, or by having a single high-speed RFIDreader that possesses the multi-item identification algorithms. Thiscapability greatly reduces the time required for library staff toprocess multiple items.

[0071] To avoid having the device perform a magnetization operation thatis inappropriate for one or more of a group of materials beingprocessed, the device may be adapted to provide a message to the userrequesting that all materials of a certain kind (books and magazines,for example) be presented together, followed by all materials of anotherkind (video and audio tapes, for example). The RFID reader can determinefrom the information obtained from individual RFID elements whether theuser has segregated the materials appropriately, and can prompt the userif he or she has not, as shown in FIG. 12. In another embodiment, thedevice includes one area for processing media of one type (books andmagazines, for example), and a separate area for processing media ofanother type (video and audio tapes, for example). The propermagnetization operation may then be reliably performed as to eachmaterial.

[0072] The device may also include a display for indicating how manyitems bearing RFID tags have been presented for processing by thedevice. That is, the RFID reader would obtain information from each itempresented to the device, and update the display to indicate that therewere, for example, five items present. An optical or other detectorcould also be used to verify that the same number of items were indeedpresent, so as to alert the patron or library staff if an item withoutan RFID tag had been inadvertently or intentionally included in thestack of other materials. Optical detectors of this type may includethose described in U.S. patent application Ser. No. 09/058,585 (Belka etal.), filed Apr. 10, 1998 and entitled “Apparatus and Method for theOptical Detection of Multiple Items on a Platform,” which is assigned tothe assignee of the present invention, the contents of which isincorporated by reference herein. Other detectors may include ones basedon weight (in which the RFID reader can determine from the RFID tag orthe LAV software the weight of the items detected, and compare it to theactual weight of the materials presented), or the number of magneticelements detected (as described in U.S. Pat. No. 5,260,690 (Mann etal.), the contents of which is incorporated by reference herein).Comparison of the number of items detected by the RFID reader and thenumber detected by an optical or other detector insures that themagnetic security elements associated with non-RFID tagged items are notdeactivated without the item also being charged out to a specificpatron. The device may process the items after a predetermined number ofitems have been presented (five items, for example), or after anoperator instructs the device to process the items, or automaticallywithout any operator intervention. A suitable display may advise theoperator as to the status of the operation.

[0073] Another embodiment of the inventive device is the ability toverify the content of a package or case having multiple items inside, asshown in FIG. 11. For example, a set of audio tapes may be packagedtogether inside a single case. To insure that only those tapes, and allof those tapes, are being processed together, the RFID reader canidentify the case, and identify each of the tapes inside the case, andmatch the identities before permitting the materials to be checked outto a patron. The RFID tag on the case may include the information as tothe contents of the case, or that information may be stored in the LAVsoftware and accessed through the identification information obtainedfrom the RFID tag.

[0074] Devices having the ability to process multiple materials furtherincreases the speed with which materials may be checked into and out ofa library. The device may be adapted to transmit only a single signal tothe LAV software system to process multiple items, and to receive only asingle signal back from that software in response.

[0075] C. Portable RFID Devices.

[0076] For a number of applications, it is desirable to provide aportable, preferably hand-held, RFID device. The hand-held RFID deviceis capable of searching among shelves, bins, piles and library carts. Itcan essentially search wherever it can be positioned close enough to theitems. It is capable of identifying multiple items that are within therange of the device. These and other features make the inventiveportable RFID device a valuable library tool. For simplicity, portableRFID devices will be described first in terms of their components andoperation, and second in terms of various useful functions for ormethods of using such devices. It is important to note that thefunctions or methods described herein are equally applicable tonon-portable RFID devices, and that the functions or methods describedabove in reference to non-portable RFID devices are similarly applicableto portable RFID devices. The different functions and methods havemerely been grouped together with the type of RFID device more oftenused to perform that function or method.

[0077] 1. Components and Operation. The hand-held RFID device of thepresent invention preferably includes an RFID reader and writer, memory,a power source, and software to enable various functions of the typesdescribed herein. The RFID reader/writer could consist of a Commander320 13.56 MHz RFID reader, manufactured by Texas Instruments of Dallas,Tex. Memory, preferably in the form of a computer, may be provided by,for example, a “palm-top” or handheld computer available from 3ComCompany of Santa Clara, Calif. under the designation Palm Pilot. Theportable computer may include an operating system, a touch-screendisplay, several buttons for developing user interfaces, a rechargestation, a docking station to transfer data between the device andanother computer, one or more ports to connect peripherals to thehand-held device (such as an RFID reader) and a battery power supply.Some units may also include a built-in peripheral such as a bar-codescanner. It may also contain various feedback systems, including lights,audio and a display.

[0078] As described above, there are a number of options fortransferring data between the hand-held device and another processingstation. A docking station approach can be used to upload or downloaddata, as shown in FIG. 14. This method could be used, for example, toupload item identification information prior to performing a search tofind those specific items. Another example would be to download datafollowing a collection of items that have been used within the library.The link could be implemented as a docking station (as illustrated); asa wireless or cabled download and/or upload; as a wireless or cabled,real-time link between the hand-held device and another processor, or inany other manner suitable for transferring such data. One such exampleis a SPECTRUM24 wireless LAN system, from Symbol Technologies ofHoltsville, N.Y. Systems like the Spectrum24 allow mobile users towirelessly communicate between mobile devices and local area networks.For this operation, the mobile unit will typically include acommunication component to support wireless communication, such asSymbol's LA 2400 Wireless LAN PC Card.

[0079] The user interface for the device is designed both to communicatethe status of searching and to allow the user to enter data. Enteringdata may include switching the device among various search modes andentering data specific to a task (for example, to check out an item, orto put an item on hold). Feedback to the user is preferably providedthrough a combination of sound, lights and a display. The display mayeither be integrated into the unit or separated. When separate, it canbe designed in various ways, including as a “wearable” display that canbe easily viewed by the user.

[0080] A particularly useful embodiment of the hand-held RFID device isas follows. A hand-held RFID device is provided in which the RFIDreader, user interface, power source, antenna, processor, and softwareare all provided in a single integrated unit, as shown in FIG. 13. Byusing a hand-held computer such as the Palm Pilot described above, anumber of real-time functions of the type described below can beachieved, in contrast to systems in which the RFID device must interactwith a separate computer, database, software system, and the like. Thesoftware can also provide either limited or full-range capabilities forsupporting functions of the type described herein, as desired. Thehand-held RFID device also preferably includes an integral power source,although it can be tethered to a larger power source of the type thatmight be worn around a user's waist. In the case of an integral powersource, the source may or may not power the processor, and may berecharged when connected to a docking station. When a hand-held computeris used, it may include its own power source, and may be recharged whenconnected to the docking station to upload and/or download information,as shown in FIG. 14.

[0081] A hand-held RFID device can interrogate and identify RFID-taggeditems whenever it is activated within range of the items. Intermittentactivation can be provided by, for example, a trigger associated withthe device, so that the elapsed time for which power is required for theRFID device is minimized. The reading distance is a function of manyfactors, but is expected to be between 15 and 45 centimeters (6 and 18inches) given current technology and the likely frequencies at which thesystem would operate. In some applications, it may be desirable torestrict the operating range of the device so that it only interrogatesRFID tags associated with items at a closer range. In other cases, thelongest available range of operation will be desired. In otherapplications, it may be preferred to restrict the output power (and thusthe reading range) to permit longer continuous operation from thebattery pack. The read range will also be influenced by the design ofthe antenna as well as the orientation of the RFID tag relative to theantenna. It should be appreciated that the read range, battery weight,and lifetime between battery recharges or replacement are oftendependent on each other. Various tradeoffs can be envisioned, based onthe particular application for the device.

[0082] In operation, a particularly useful feature of a hand-held deviceis obtaining real-time information regarding an item that has beenscanned by the device. That is, the hand-held device obtains informationfrom the RFID tag, and either immediately displays that information, orimmediately displays information stored within the hand-held device thatis related to the tagged item. This is in contrast to devices that mustbe docked with or otherwise communicate with a separate database ofinformation before that information can be displayed for the user. Thehand-held device of the present invention can also be docked or canotherwise communicate with a separate database, if such features aredesired.

[0083] 2. Functions, Methods, and Applications. The hand-held RFIDdevice of the present invention can be used for a number of functions,methods, and applications, including the following.

[0084] The inventive handheld RFID device has particular usefulness initem location. For example, the device could be programmed with specificinformation identifying certain items that an operator wishes to locate.The unique identifier for each desired item would be stored in areserved memory location in the handheld computer. As the identifiersof, for example, items on a shelf were read by the RF reader, each wouldbe compared, using standard software routines known to those skilled inthe art, with the list of items stored in memory. When a match occurred,the device would then create one or more visual, audio, tactile, orother signals indicating the presence of the item. One application forthis function includes locating items that are believed to be missing. Alibrary typically maintains a list of missing items—those items that areexpected to be in the library, but cannot be found. By downloading thosemissing item identifiers to the hand-held device, the operator can passthe device by items and obtain feedback when a missing item isencountered.

[0085] Another example is to locate items that have not circulated orbeen used within a given number of months. Again, the identifiers ofthose items could be downloaded to the hand-held device for searching.Alternatively, the circulation counts can be maintained directly on thememory of the RFID tag. In this case, the hand-held device does not needto download any data from another computer system. The hand-held deviceonly compares RFID memory data to established criteria and providesfeedback to the operator based on the selected parameters.

[0086] Another example of where data can be either downloaded from alibrary data base to the hand-held device or obtained directly from theRFID tag is to locate items in the library that have not been checkedin. A list of items not checked-in could be obtained and then downloadedto the hand-held device or the RFID tag could maintain a memory locationto indicate the check-in status of an item. When the RFID tag memoryindicates the check-in status, the hand-held device does not need anydata from an external database to perform the search. A naturalapplication of obtaining matching data directly from the RFID tag is tolocate items that belong to different library buildings or to differentlibrary systems. For this application, the owning library is preferablyencoded onto the RFID tag and the hand-held device alerts the operatorwhen an RFID tag with a different owning library code is encountered.The hand-held RFID device could also be used to determine, as with theRFID device described above, whether all members of a set of associateditems are present together, as with the tapes in a books-on-tape case.

[0087] The RFID device of the present invention could also be used toverify the order of materials on a shelf. In this mode, the device isscanned across one or more rows of items. The device reads each item andindicates, to the operator, which items are not shelved in the correctorder. As input, the device has access to the shelving algorithm used bythe library for the section being scanned. Possible algorithms include:Dewey Decimal order, Library of Congress order, and Author lastname/Title order. Other methods of sorting, as determined by eachlibrary, are possible.

[0088] Another method of establishing shelf information is to associateeach item with a location. Shelf locations can be as specific or asgeneral as the library desires. For example, a general shelf locationmight include all “Adult Fiction titles.” A more specific shelf locationmight be “Adult Fiction, Authors AA-AB.” In the preferred embodiment,the shelf location for an item is encoded directly in the RFID tagmemory for that item. An indexing system may also be used to savememory, so that a short code number is used to indicate a shelflocation. For example, the number 1 could represent Adult Fiction, thenumber 2 could represent Juvenile Fiction, and so on. The amount ofmemory needed to store all shelf locations depends on the number oflocations within a library. Another embodiment is to obtain the desiredshelf location from a library database and then download those locationsas part of the transfer of data to the hand-held device.

[0089] When items are associated with a shelf location, by either methodabove, the operator can use the hand-held device to locate items thatare in the wrong location. Two processing methods can be used todetermine which shelf location is currently being processed in order tosearch for items with non-matching locations. In one embodiment, thecorrect shelf location is obtained by reading several RFID tags andheuristically processing the data to infer a location. For example, ifthe RFID device reads a certain number of tags that are indexed to theAdult fiction area, the device can be programmed to alert the user whennon-Adult Fiction items are encountered. In another embodiment, thelibrary places “location tags” on the shelves or other locations to besearched. These location tags are first read by the hand-held device toindicate that subsequent items read should belong to that location andan alert is provided when a mismatch occurs.

[0090] In another embodiment, the hand-held RFID device may be used toenter data into the device as to a specific item. That information maybe either transmitted immediately and directly to the LAV software, ormay be transmitted subsequently when the hand-held device is reconnectedto a docking station and downloads the information to the LAV software.For example, when a user takes a library material from its location, theuser may input the new status of the article into the hand-held RFIDdevice. Because this information must be entered into the LAV softwareeventually, it saves the operator time to be able to indicate this statedirectly and immediately as opposed to waiting until he or she canaccess an LAV software system terminal.

[0091] In yet another embodiment, the hand-held device could be used toprovide additional information about a specific item once the item hasbeen obtained and its RFID tag scanned by the RFID device. For example,library staff may collect materials that have been used in the library,and scan those materials either to obtain more information about thatmaterial (who last checked it out; how often has it been used) or toprovide information to a database that generates statistical profiles oflibrary material usage, or both. The operator simply reads the RFID tagsof the items as they are collected from the various locations in thelibrary at which they were used. As items are collected, the operatorcan also indicate from where the items were collected by selecting froma list of locations, entering a location code or reading a “locationRFID Tag” that is associated with that location and would preferably beaffixed to or near that location. In this way, the library staff is ableto obtain additional information about where in the library suchmaterials were used. Alternatively, if items used in the library arefirst placed on a book cart, for example, the hand-held device couldmake a single pass by the items on the cart to record them. Thefunctions described in this paragraph are referred to herein as“sweeping.”

[0092] The benefits of a hand-held RFID device are numerous, and includethe ability to locate items more quickly and accurately compared toreading each call number or title from items, the ability to “get close”to desired item quickly and then examine items more closely to locateitem of interest, the ability to quickly identify items matching a givenset of criteria (lost, not checked out, matching specific circulationvalues, etc.), and the ability to identify items that are mis-shelvedand indicate, to the operator, the correct location for the items. Thiswould include items that don't belong in the collection being scanned.Other advantages include the ability to enter transactions directly intothe hand-held unit when items are located, the ability to identify anitem without having to scan a bar code or any other markings on theitem, such as author, title and call number, and the ability todetermine if a given item is somewhere on a shelf, on a library cart, ina bin, on a table or even in a pile. These and other advantages will beapparent to those of skill in the art.

[0093] In the claims appended hereto, persons of ordinary skill willrecognize that the items recited could be library materials (includingbooks, periodicals, magnetic or optical media, and the like), or couldbe other completely unrelated materials such as packages, letters,paintings, electronic devices, animals, automobiles, bicycles, or anyother items of value.

We claim:
 1. An RFID device for processing items having an RFID elementand a magnetic security element associated therewith, comprising: (a) anRFID interrogation source for interrogating and obtaining informationfrom the RFID element; and (b) a magnetization system for performing anappropriate magnetization operation on the magnetic security element inresponse to the information obtained from the RFID element.
 2. The RFIDdevice of claim 1, wherein the device determines the appropriatemagnetization operation directly in response to information obtainedfrom and contained within the RFID element itself.
 3. The RFID device ofclaim 1, wherein the device determines the appropriate magnetizationoperation after the information obtained from the RFID element has beencompared to information in a database separate from the RFID element. 4.The RFID device of claim 1, wherein the device is adapted to provide anindication that an item is a specific type of item.
 5. The RFID deviceof claim 2, wherein the device is adapted to perform no magnetizationoperation in response to the information obtained from the RFID element.6. The RFID device of claim 1, wherein the device further comprises anoptical bar code scanner.
 7. The RFID device of claim 6, in whichinformation obtained by the optical bar code scanner may be written toan RFID tag to be associated with the item.
 8. The RFID device of claim1, wherein the device further comprises a computer.
 9. The RFID deviceof claim 8, wherein the computer is adapted to operate libraryautomation vendor software for managing the flow of materials into andout of a library.
 10. The RFID device of claim 1, wherein the RFIDinterrogation source interrogates and obtains information about the RFIDelement regardless of the orientation of the RFID element relative tothe interrogation source.
 11. A method of performing a magnetizationoperation on a magnetic security element associated with an item,comprising the steps of: (a) interrogating an RFID element associatedwith that item to obtain information; (b) using the information todetermine the type of item with which the RFID element is associated;and (c) performing an appropriate magnetization operation on themagnetic security element based on the type of material with which it isassociated.
 12. The method of claim 11, wherein the item comprisesmagnetically-recorded media, and the magnetization operation is theapplication of a magnetic field to the magnetic security element that issufficient to activate or deactivate the element without damage to themagnetically-recorded media.
 13. The method of claim 11, wherein theappropriate magnetization operation is the absence of magnetization. 14.A method of processing a set of associated items each having an RFIDelement, comprising the steps of: (a) interrogating each of the items toobtain information including the identity of the item; (b) interrogatingan RFID element that is associated with the set of associated items; (c)comparing the information obtained in step (a) with the informationobtained in step (b) to determine whether the associated items arepresented together.
 15. The method of claim 14, wherein the methodfurther includes the step of: (d) determining whether other items areincluded with the associated items that are not members of the set ofassociated items.
 16. The method of claim 14, wherein the method furtherincludes the step of: (d) determining whether any of the associateditems are missing from the set.
 17. The method of claim 14, wherein themethod further includes the step of: (d) performing a magnetizationoperation on magnetic security elements associated with the items.
 18. Amethod of processing multiple items each having an RFID element,comprising the steps of: (a) presenting more than one of said items toan RFID reader; (b) obtaining information from the RFID elementsapproximately simultaneously; and (c) using the information obtainedfrom the RFID elements to determine whether different types of items areamong the items presented.
 19. The method of claim 18, wherein themethod further includes the step of: (d) providing an indication to auser that different types of items are among the items presented.
 20. Amethod of processing multiple items having an RFID element, comprisingthe steps of: (a) presenting more than one of the items to an RFIDreader; (b) obtaining information from the RFID elements approximatelysimultaneously; (c) detecting the number of RFID elements presented; (d)automatically processing the items when only a predetermined number ofitems have been detected.
 21. The method of claim 20, wherein theprocessing step comprises performing an appropriate magnetizationoperation on magnetic security elements associated with the itemspresented to the RFID reader.
 22. The method of claim 20, wherein theprocessing step comprises updating a database that includes informationas to the items presented to the RFID reader.
 23. A method of processingmultiple items having an RFID element, comprising the steps of: (a)presenting more than one of the items to an RFID reader; (b) obtaininginformation from the RFID elements approximately simultaneously; (c)detecting the number of RFID elements presented; (d) displaying thenumber of RFID elements detected to a user; and (e) permitting the userto direct that the items be processed.
 24. The method of claim 23,wherein the processing step comprises performing an appropriatemagnetization operation on magnetic security elements associated withthe items presented to the RFID reader.
 25. The method of claim 23,wherein the processing step comprises updating a database that includesinformation as to the items presented to the RFID reader.
 26. Ahand-held RFID device, comprising as an integrated unit: (a) a computer;(b) an antenna to transmit commands between an RFID tag and an RFIDreader; (c) an RFID reader for reading information from multiple RFIDelements substantially simultaneously; and (d) a display.
 27. Thehand-held RFID device of claim 26, further comprising: (d) an RFIDwriter for transmitting information to an RFID element for storagetherein.
 28. The hand-held RFID device of claim 26, further comprising:(d) a data transfer system for transferring data from the RFID device toa separate database.
 29. The hand-held RFID device of claim 28, whereinthe data transfer system comprises a connection for operatively couplingwith a docking station.
 30. The hand-held RFID device of claim 28,wherein the data transfer system comprises a cabled data transferconnection.
 31. The hand-held RFID device of claim 28, wherein the datatransfer system comprises a wireless data transfer system.
 32. Thehand-held RFID device of claim 26, wherein the device includes anintegral power source.
 33. The hand-held RFID device of claim 26,wherein the computer is a detachable hand-held computer.
 34. Thehand-held RFID device of claim 33, wherein the computer includes a powersource separate from the source of power for the remainder of thedevice.
 35. The hand-held RFID device of claim 33, wherein thedetachable hand-held computer comprises a connection for operativelycoupling with a docking station.
 36. The hand-held RFID device of claim26, further comprising: (d) an information input system for providinginformation to the RFID device other than by radio frequencyinterrogation.
 37. A method of using a portable RFID device, comprisingthe steps of: (a) inputting information to the device describing acertain item or class of items each having an RFID element; and (b)scanning a plurality of items to determine whether the certain item oritems are present.
 38. The method of claim 37, wherein the informationis selected from information describing missing items, items that havenot been used within a specified period of time, items that have notbeen checked into inventory, items that have been designated for holdstatus, and the owner of the items.
 39. The method of claim 37, whereinthe information is contained within and available from the RFID elementitself.
 40. The method of claim 37, wherein the method further includesthe step of: (c) providing an indication in real time to a user that theitem or items of interest were located.
 41. The method of claim 40,wherein the method further includes the step of: (d) recording in adatabase that the item or items of interest were located.
 42. A methodof using a portable RFID device, comprising the steps of: (a) inputtingan algorithm to the device that describes an ordered set of items; (b)scanning a plurality of items having RFID elements to obtain informationfrom those elements; and (c) comparing a description of the itemsobtained using the information obtained from the RFID elements to thealgorithm to determine whether the scanned items are in the algorithmorder.
 43. The method of claim 42, wherein the method further comprisesthe step of: (d) providing an indication to a user of any item that isnot in the algorithm order.
 44. The method of claim 43, wherein theindication is provided in real time.
 45. The method of claim 43, whereinthe indication is provided in response to information obtained from adatabase separate from the RFID device and the RFID tag.
 46. The methodof claim 42, wherein the algorithm is based on an ordering system thatis selected from the Dewey Decimal System, the Library of CongressSystem, an alphabetical listing of authors, and an alphabetical listingof topics.
 47. A method of using a portable RFID device to associate anitem bearing an RFID element with a location, comprising the steps of:(a) scanning the RFID element associated with the item; (b) inputtinginformation to the device to describe the location; and (c) associatingthe item with the location in a database.
 48. The method of claim 47,wherein the location has a separate RFID element, and step (b) comprisesscanning the RFID element associated with that location.
 49. A method ofusing a portable RFID device to associate a certain item bearing an RFIDelement with a location having a group of items of a similar type eachalso bearing an RFID element, comprising the steps of: (a) scanning theRFID element associated with the item; (b) scanning the RFID elements ofat least one additional item within the group of items; (c) determiningwhether the certain item belongs with the group of items.
 50. The methodof claim 49, wherein the method further comprises the step of: (d)providing an indication of the determination made in step (c) to theuser in real time.
 51. A method of using a portable RFID device,comprising the steps of: (a) obtaining an item having an RFID elementassociated therewith; (b) using the portable RFID device to interrogatethe RFID element and obtain information therefrom; and (c) inputtinginformation to the RFID device as to that item by other than RFIDinterrogation.
 52. The method of claim 51, wherein the method furtherincludes the step of: (d) using the information input in step (c) toupdate a database that includes information as to that item.
 53. Themethod of claim 52, wherein the database is updated when the portableRFID device is connected to a docking station to download information tothat database.
 54. A method of using a portable RFID device with an itemhaving an RFID element associated therewith, comprising the steps of:(a) interrogating the RFID element with the RFID device to obtaininformation therefrom; (b) identifying the item using the informationobtained; and (c) requesting from the portable RFID device furtherinformation regarding the item.
 55. The method of claim 54, wherein theinformation requested in step (c) is obtained from memory containedwithin the portable RFID device.
 56. The method of claim 54, wherein theinformation requested in step (c) is obtained from memory that isseparate from the portable RFID device and is transferred to the device.57. A method of using an RFID device, comprising the steps of: (a)interrogating a group of items each bearing an RFID tag; (b) providingto the RFID device information identifying a certain class of items; and(c) receiving in real time from the RFID device an indication of itemsthat are not within the certain class of items.
 58. The method of claim57, wherein the class of items are items associated with a particularlocation, and the information provided in step (b) includes thatlocation.
 59. A method of using an RFID device with items of interestthat bear an RFID tag, comprising the steps of: (a) interrogating thetagged items with the RFID device; and (b) entering information into theRFID device describing the location of the item of interest.
 60. Themethod of claim 59, further comprising the step of: (c) collecting in adatabase the information entered in step (b) regarding the items ofinterest.
 61. The method of claim 60, wherein the database is containedwithin the RFID device.
 62. The method of claim 60, wherein the databaseis separate from the RFID device, and the information is transferred tothat database.